Predictive Genetic Testing

Predictive genetic testing is a trending scientific advancement that could assist coaches and supporting sport science staff in the development of training plans and goals for their athletes. Learning more about an athlete’s genome (their genetic map) could optimize an athlete’s ability to achieve peak performance by understanding more about how they may respond to specific training and nutrition interventions. This approach may not only impact performance outcomes, but can help identify if an athlete is at higher risk for injury or if they exhibit other traits that may impact training or nutrition adaptations. 1 There are many different (sport) genetic testing companies now popping up in the marketplace who offer easily accessible, consumer direct genetic testing, but is their information credible and are there any risks associated with genetic testing? We will review some of the current evidenced-based literature so that you can make the most educated decision on whether this is the right choice for you and your athlete.

How they work?

Genetic tests can predict an athlete’s traits by determining specific and scientifically identified genes that may impact athletic performance, nutrition, risk of injury, or other behaviours. 1 The weight, or value, of each gene is assessed for importance, as some genes have a larger contribution to athletic performance than others. 1 Some of the most common physiological traits that are related to sport performance and can be predicted by genetic testing include; muscular endurance, muscular power, strength training, risk of injury, and metabolism. 1 Thus, by understanding more about an athlete’s genome, we can potentially improve training results by tailoring training plans that can target an athlete’s area of genetic weakness/sensitivities. The same can be done with tailoring nutrition interventions. If an athlete’s genome reveals certain metabolic sensitivities or physiological traits, sports dietitians can adapt their nutrition plans to meet their specific needs, necessary for achieving desired training and performance outcomes. For example, if an athlete requires improvement in muscular endurance and thus relies on the body’s ability to supply oxygen to the muscles via red blood cells, it would be beneficial to have supporting information as to HOW that athlete may produce red blood cells since we know that essential vitamins (folate, Vitamin B12) and minerals (iron) are needed for red blood cell production and growth.

Many digestive and metabolic functions rely on the body’s pool of certain enzymes. Genetic tests can help identify if they have the correct and enough of these enzymes required for metabolizing vitamins or minerals. This is particularly important when trying to optimize an athletes training adaptations, as we know that having certain sufficient nutrients supports many training interventions .1

Potential Advantages of Genetic Tests

Here are two examples that demonstrate the advantages to knowing an athlete’s genome in order to tailor their nutrition plan are:

Athletes who rely on power for their sport have a higher concentration of fast twitch muscle fibre types that are dictated by an athlete’s genetics. This can infer that they may require an increased need for dietary protein for proper recovery.1 Coaches and athletes that are at risk for soft tissue injuries may want to incorporate gelatin and Vitamin C into the athlete’s diet to help with soft tissue repair. 2

Genetic testing can also assist in designing more personalized weight or body composition management nutrition approaches by identifying if they may be more susceptible to weight gain, or loss, due to their genetic ability to metabolize different types of nutrients such as fat.1

Potential Risks of Genetic Tests

To date, some potential risks with predictive genetic testing have been identified, and we will discuss two as they may relate to athletes.

Many countries have laws that protect individuals from genetic discrimination, unfortunately to date, Canada does not. 3 Bill S-201 (Genetic Non-Discrimination Act) is in the development phases in parliament now and is to protect Canadians from genetic discrimination.3 Without a non-discrimination act, predictive genetic testing could be abused and used as a form of talent identification.4

Since genetic testing is still in its infancy, there are a lot of unknowns about what other factors may impact genes and their effect on future health outcomes. 4 For example, scientists have previously identified genes that are associated with improved athletic performance to later discover that the same gene has an increased risk for Alzheimer’s disease which may affect the athlete who was tested.4

It may be prudent to recommend genetic counselling before deciding whether or not genetic testing is right for your athlete in that particular situation, so that a more informed choice can be made.4

Recommendations for Use

Predictive genetic tests are advised to be used only to identify an athlete’s strengths and weaknesses for the purpose to help them improve training adaptations and to achieve peak performance. 4 Genetic testing is not meant to be used as a means of talent identification, or to have any athlete discriminated against due to their genome. To date, research supports that some genetic combinations are beneficial for sport performance, but it must be noted that not all of the potential genes have been discovered, and furthermore, future polymorphisms, or mutations, may have larger contributions to sport performance. 4 Finally, genetics are only one piece of the puzzle. There are many other factors that are involved with developing an athletes’ potential which include, but not limited to: anthropometrics, biochemical measurements, technical skill, social, and environmental factors. Clearly there is still much more research in this innovative area of genetic testing for the purpose of tailoring athletes training programs for the enhancement of performance and recovery.

The Potential of Being an Elite Athlete (Mid-Long Distance Running Example)

The total number of elite male or female mid-long distance runners at any given time due to environmental, social, and genetic factors is approximately 13 males and 14 females. Genetics account for only a portion of elite athletes’ potential, but are only a small piece of the puzzle. 5 Coaching and training are required for athletes to achieve their genetic potential. The above infographic is adapted from “Olympic Genes on the Podium?” that represents the proportion of the population for each identified factor. 5

The Bottom Line

Genetic testing remains in its infancy, with a limited, but growing body of research to support and connect genetic contributions to athletic performance. Learning more about an athlete’s genome could no doubt help tailor training programs by giving coaches valuable insight and a competitive training edge, but it is important to review the current body of evidence and make an informed choice whether genetic testing is right for you and/or your athlete in a given situation, before you invest.